In the forty years to 2019, the level and sources of taxes in OECD countries had remained roughly constant. However, this apparent stability had concealed serious threats to the nature of public finance. First, public expenditures had grown over that same period, particularly following the 2008-09 global financial crisis. Second, traditional sources of taxation, namely taxes on labour income and consumption, which together accounted for about 85% of tax revenue, were coming under threat by a number of emerging technological and social phenomena, including advancements in job-replacing automation; a growing gig economy; greater cross-border e-commerce; an ageing population; and an increasing concentration of wealth. All of these changes suggested the need for a fundamental redesign of the tax system. 

This background note, written for non-tax experts, explores how these phenomena challenge the legacy approaches used to tax labour and capital. It discusses ways to rethink tax systems for the 2020s and beyond, with a particular look at two bold, yet controversial, new policy ideas: an automation tax and a tax on global wealth.